1. Field of the Invention
This invention relates to the field of golf putters. More specifically, the invention comprises a golf putter having variable loft on the face of the putter.
2. Description of the Related Art
Golf clubs primarily include irons, woods and putters. A putter is designed to allow a golfer to hit from the green or the fringe of the green. Putting is typically thought of as the most precise aspect of the game of golf. A putter is therefore designed with precision in mind.
As shown in FIG. 1, a putter 10 generally has a shaft 12, head 14, hosel 20 and putter face 16. Each component part of a putter can vary to achieve different results. The face 16 of a putter perhaps offers the most variety between different putters. For example, a putter face 16 can contain grooves, an insert 18 of strips of metal or a softer polymer material. A degree of loft, or angle at which the club face lies, can be imparted to the club face. Thus, dependent on the type of putter face 16 utilized on a putter, a broad range of results can be achieved upon impact with the golf ball. Further, the hosel 20 can be bent (or angled) to give putter face 16 a different degree of loft relative to the shaft 12. This may be done to “fit” the putter to a particular golfer.
Referring to FIG. 2, the loft angle 22 is the angle at which the club face 16 lies relative to the vertical axis of the shaft 12 (i.e. angle between the line of club shaft orientation, arm A 24 and the club face plane 26). Manipulating, or bending, the hosel 20 impacts the angle of club face 16. For purposes of the present description the loft angle 22 will be called the “static loft angle” 22, thereby differentiating it from “dynamic loft” described herein. As loft increases more lift will be imparted to the ball. Typically, putter faces are flat and have some degree of loft. While the static loft angle in putters is less than the static loft angle in irons, the static loft angle still has a substantial effect on the path of travel of the golf ball.
It should be noted that loft at impact, or dynamic loft, can be significantly different than the “static loft” (described above) of the putter face. The dynamic loft, illustrated in FIG. 3, is the angle determined by the lean of the shaft and the path of the club head as the golfer swings and approaches the ball. The vertex of the dynamic loft angle 28 is located at the point of impact 30. The dynamic loft angle 28 is the angle at which the plane of the club face 32 lies relative to a vertical line extending along the central axis of the golf ball, or arm B 34. Thus the dynamic loft angle 28 is a combination of the static loft angle of the club face and how the golfer leans the shaft 12 and approaches the ball 36.
As shown in FIG. 4, the launch angle 38 is the angle at which the golf ball 36 is launched into the air after contacting putter face 16. Launch vector 40 shows the projected path of golf ball 36. Launch angle 38 is the angle measured between launch vector 40 and horizontal plane 42, or a plane relative to the ground 44. Both the dynamic loft angle and static loft angle effect the launch angle 38. Or, in other words, the plane in which the putter face lies and the angle of approach on the golf ball effect the path of the golf ball after it is struck. However, these two factors should only be considered as two among many factors which affect the degree of launch angle 38.
When a golfer putts a ball it initially skids along the ground before it begins to roll. Minimizing the amount of skid of the ball increases the control the golfer retains over the ball. True roll is considered the moment that the ball achieves top-spin without skidding sideways and/or retaining backspin. The quicker the ball achieves true roll the more control the golfer has over the path and distance the golf ball travels.
Prior art putters have been designed with a flat or rounded face surface. When struck, with a positive launch angle, the golf ball typically slides or rolls up the club face and releases from the club with backspin; when it hits the ground some skidding results. A ball struck at too great of a positive launch angle can cause the ball to travel too far over the top of the grass, landing with additional backspin, causing skid and bounce. On a flat hard surface a golf ball hit on the upper portion of the ball with the bottom of the putter face would cause the ball to reach a true roll quickly with minimal skid. However, on the golf course, the ball sits slightly down in the grass, even on a flat green. Thus, hitting downward, or “topping” the ball will drive the ball into the ground, causing the ball to bounce thereby reducing control over distances. There is an optimal launch angle which encourages the ball to slightly lift, travel over the ground and reach a true roll quickly. However, even at the optimal launch angle, the golf ball will have an undesired amount of backspin due to the nature of the putter face. Thus, it would be desirable to have a putter face which encourages minimal backspin when struck with a desired launch angle.
After considering the principals affecting the launch angle of the golf ball, it can be inferred that a golfer who consistently strikes downward on the golf ball would benefit from a putter face having a static loft angle greater than the desired launch angle. The static loft angle, in this scenario, would overcorrecting for the golfer's erroneous dynamic loft angle, thereby achieving the desired launch angle for the golf ball. In the alternative, a golfer who consistently meets the golf ball at a positive 5° dynamic loft, for example, may benefit from a golf club having a smaller degree of static loft.
However, typically golfers are not aware of the relevance of dynamic loft or their own particular tendency at impact. Furthermore, golfers are not always consistent in their lean or angle of approaching and striking a golf ball. It is difficult to fit a particular golfer with the appropriately “lofted” club for ideal putting.
Additionally, prior art putters have been designed with the incorrect notion that the desired launch angle lies somewhere between positive 3-4°. It follows that most prior art putters are designed with a consistent loft angle between positive 2.5° and positive 5°. However, the desired launch angle, as further described herein, actually lies between positive 2-2.5°.
Therefore, what is needed is a putter which automatically provides for a corrective club face loft (“static loft”) dependent on the angle of approach and lean of the shaft of the individual golfer whereby the golfer can achieve a desired launch angle between positive 2-2.5°. It is also desirable to produce a club face which reduces the amount of backspin imparted to the golf ball upon launch. The present invention achieves these objectives, as well as others that are explained in the following description.